Hmm i always get stuck doing to much in any sized family 
Reason i suggested 4 man fam is you get 1 banker 1 ressie 1 attacker 1 inactive or if your lucky what ever role you see fit haha.
Less players to rely on.
Atm if you have a 5 man fam but only 3 players join your kinda hurting badly with a 4 man fam and 2-3 join you can still wing it just as well.
But i see you point. One thing id like to ask everyone is why is it bad of expo phase never ends? Doesnt it just make things more ingesting and strategic